RNA regulatory element BLE1 directs the early steps of bicoid mRNA localization

Development ◽  
1993 ◽  
Vol 118 (4) ◽  
pp. 1233-1243 ◽  
Author(s):  
P.M. Macdonald ◽  
K. Kerr ◽  
J.L. Smith ◽  
A. Leask
Keyword(s):  
Untranslated Region ◽  
Regulatory Element ◽  
Essential Element ◽  
Mrna Localization ◽  
Morphogen Gradient ◽  
Anterior Pole ◽  
Functional Elements ◽  
Cis Acting ◽  
Localization Signal ◽  
Drosophila Embryos

Deployment of the bicoid morphogen gradient in early Drosophila embryos requires the prelocalization of bicoid mRNA to the anterior pole of the egg. This anterior localization is mediated by a cis-acting localization signal contained within the 3′ untranslated region of the bicoid mRNA. Here we use a series of bicoid transgenes carrying small deletions in the 3′ untranslated region to survey for functional elements that constitute the localization signal. We identify and characterize one essential element, BLE1, which specifically directs the early steps of localization. In addition, we find that many deletions within the bicoid mRNA 3′ untranslated region impair but do not prevent localization. One such deletion specifically interferes with a later step in localization. Thus the bicoid mRNA localization signal appears to consist of multiple different elements, each responsible for different steps in the localization process.

Components acting in localization of bicoid mRNA are conserved among Drosophila species.

Genetics ◽  
1994 ◽  
Vol 137 (2) ◽  
pp. 521-530 ◽  
Author(s):  
S K Luk ◽  
M Kilpatrick ◽  
K Kerr ◽  
P M Macdonald
Keyword(s):  
Mrna Localization ◽  
Drosophila Virilis ◽  
Drosophila Species ◽  
Drosophila Pseudoobscura ◽  
Anterior Pole ◽  
Early Step ◽  
Cis Acting ◽  
Body Patterning ◽  
Localization Signal ◽  
Evolutionary Comparisons

Abstract Substantial insights into basic strategies for embryonic body patterning have been obtained from genetic analyses of Drosophila melanogaster. This knowledge has been used in evolutionary comparisons to ask if genes and functions are conserved. To begin to ask how highly conserved are the mechanisms of mRNA localization, a process crucial to Drosophila body patterning, we have focused on the localization of bcd mRNA to the anterior pole of the embryo. Here we consider two components involved in that process: the exuperantia (exu) gene, required for an early step in localization; and the cis-acting signal that directs bcd mRNA localization. First, we use the cloned D. melanogaster exu gene to identify the exu genes from Drosophila virilis and Drosophila pseudoobscura and to isolate them for comparisons at the structural and functional levels. Surprisingly, D. pseudoobscura has two closely related exu genes, while D. melanogaster and D. virilis have only one each. When expressed in D. melanogaster ovaries, the D. virilis exu gene and one of the D. pseudoobscura exu genes can substitute for the endogenous exu gene in supporting localization of bcd mRNA, demonstrating that function is conserved. Second, we reevaluate the ability of the D. pseudoobscura bcd mRNA localization signal to function in D. melanogaster. In contrast to a previous report, we find that function is retained. Thus, among these Drosophila species there is substantial conservation of components acting in mRNA localization, and presumably the mechanisms underlying this process.

bicoid mRNA localization signal: phylogenetic conservation of function and RNA secondary structure

Development ◽  
1990 ◽  
Vol 110 (1) ◽  
pp. 161-171 ◽  
Author(s):  
P.M. MacDonald
Keyword(s):  
Comparative Analysis ◽  
Secondary Structure ◽  
Rna Secondary Structure ◽  
Rational Design ◽  
Mrna Localization ◽  
Anterior Pole ◽  
Noncoding Regions ◽  
Cis Acting ◽  
Phylogenetic Conservation ◽  
Localization Signal

Transcripts of the bicoid (bcd) gene are localized to the anterior pole of the Drosophila oocyte, thereby allowing formation in the embryo of an anteroposterior gradient of the bcd protein morphogen. We previously showed that a 630 nucleotide portion of the 3′ noncoding region of the bcd mRNA is necessary for this localization, and is sufficient to confer anterior localization on a heterologous transcript. Here I have used a comparative analysis to begin to more precisely define the cis-acting mRNA localization signal. The bcd genes from six additional Drosophila species were cloned, and DNA of the 3′ noncoding regions sequenced. Three of these regions were tested interspecifically for mRNA localization in D. melanogaster and each functioned correctly; these regions must therefore contain the cis-acting signal. The primary sequences, which are up to 50% divergent from the D. melanogaster gene, show patchy homology throughout most of the region. Interestingly, all seven species can potentially form a large stereotypic secondary structure. This structure is a likely candidate for the localization signal and can be used for the rational design of mutations to test that possibility.

scholarly journals A negative regulatory element in the bcl-2 5'-untranslated region inhibits expression from an upstream promoter.

1993 ◽  
Vol 13 (6) ◽  
pp. 3686-3697 ◽  
Author(s):  
R L Young ◽  
S J Korsmeyer
Keyword(s):  
B Cell ◽  
Cell Lines ◽  
Untranslated Region ◽  
Regulatory Element ◽  
Cell Development ◽  
Negative Control ◽  
B Cell Development ◽  
Negative Regulatory Element ◽  
Cis Acting ◽  
B Lineage

bcl-2 mRNA is present at high levels in pre-B-cell lines but is down-regulated in most mature B-cell lines. To investigate the mechanisms responsible for its developmental control, we studied the regulation of bcl-2 expression in human B-lineage cell lines. Using nuclear run-on assays, we found that bcl-2 transcription decreases in parallel with levels of steady-state mRNA during B-cell development. To define cis-acting elements that regulate bcl-2 transcription, we analyzed the expression of transiently transfected promoter-reporter constructs. We identified a novel negative regulatory element (NRE) in the bcl-2 5'-untranslated region that decreased expression from the bcl-2 P1 promoter or heterologous promoters in a position-dependent fashion. The NRE functions in either orientation but contains distinct orientation-dependent subfragments. Additional analyses demonstrated that multiple, functionally redundant sequence elements mediate NRE activity. Though the bcl-2 NRE is active in pre-B- and mature B-cell lines, chromatin structure of the endogenous NRE differs in these cells, suggesting that its activity or effect may vary during B-cell development. Our results indicate that negative control of transcription initiated at the P1 promoter is an important determinant of the differential expression of bcl-2.

scholarly journals Recognition of the bcd mRNA Localization Signal in Drosophila Embryos and Ovaries

2005 ◽  
Vol 25 (4) ◽  
pp. 1501-1510 ◽  
Author(s):  
Mark J. Snee ◽  
Eric A. Arn ◽  
Simon L. Bullock ◽  
Paul M. Macdonald
Keyword(s):  
Protein Complexes ◽  
Regulation Of Gene Expression ◽  
Mrna Localization ◽  
Signal Recognition ◽  
Recognition Mechanism ◽  
Stem Loop ◽  
Multiple Contexts ◽  
Polarized Cells ◽  
Localization Signal ◽  
Drosophila Embryos

ABSTRACT The process of mRNA localization, often used for regulation of gene expression in polarized cells, requires recognition of cis-acting signals by components of the localization machinery. Many known RNA signals are active in the contexts of both the Drosophila ovary and the blastoderm embryo, suggesting a conserved recognition mechanism. We used variants of the bicoid mRNA localization signal to explore recognition requirements in the embryo. We found that bicoid stem-loop IV/V, which is sufficient for ovarian localization, was necessary but not sufficient for full embryonic localization. RNAs containing bicoid stem-loops III/IV/V did localize within the embryo, demonstrating a requirement for dimerization and other activities supplied by stem-loop III. Protein complexes that bound specifically to III/IV/V and fushi tarazu localization signals copurified through multiple fractionation steps, suggesting that they are related. Binding to these two signals was competitive but not equivalent. Thus, the binding complexes are not identical but appear to have some components in common. We have proposed a model for a conserved mechanism of localization signal recognition in multiple contexts.

A conserved 90 nucleotide element mediates translational repression of nanos RNA

Development ◽  
1996 ◽  
Vol 122 (9) ◽  
pp. 2791-2800 ◽  
Author(s):  
E.R. Gavis ◽  
L. Lunsford ◽  
S.E. Bergsten ◽  
R. Lehmann
Keyword(s):  
Translational Control ◽  
Untranslated Region ◽  
Translational Regulation ◽  
Critical Role ◽  
Rna Localization ◽  
Translational Repression ◽  
Regulatory Function ◽  
Control Element ◽  
Cis Acting ◽  
Localization Signal

Correct formation of the Drosophila body plan requires restriction of nanos activity to the posterior of the embryo. Spatial regulation of nanos is achieved by a combination of RNA localization and localization-dependent translation such that only posteriorly localized nanos RNA is translated. Cis-acting sequences that mediate both RNA localization and translational regulation lie within the nanos 3′ untranslated region. We have identified a discrete translational control element within the nanos 3′ untranslated region that acts independently of the localization signal to mediate translational repression of unlocalized nanos RNA. Both the translational regulatory function of the nanos 3′UTR and the sequence of the translational control element are conserved between D. melanogaster and D. virilis. Furthermore, we show that the RNA helicase Vasa, which is required for nanos RNA localization, also plays a critical role in promoting nanos translation. Our results specifically exclude models for translational regulation of nanos that rely on changes in polyadenylation.

Multiple cis-acting targeting sequences are required for orb mRNA localization during Drosophila oogenesis

1994 ◽  
Vol 14 (4) ◽  
pp. 2235-2242
Author(s):  
V Lantz ◽  
P Schedl
Keyword(s):  
Untranslated Region ◽  
Germ Line ◽  
Critical Role ◽  
Positional Information ◽  
Mrna Localization ◽  
Early Embryo ◽  
Developmental Systems ◽  
Localization Pattern ◽  
Cis Acting ◽  
Anterior Posterior

The targeting of positional information to specific regions of the oocyte or early embryo is one of the key processes in establishing anterior-posterior and dorsal-ventral polarity. In many developmental systems, this is accomplished by localization of mRNAs. The germ line-specific Drosophila orb gene plays a critical role in defining both axes of the developing oocyte, and its mRNA is localized in a complex pattern during oogenesis. We have identified a 280-bp sequence from the orb 3' untranslated region capable of reproducing this complex localization pattern. Furthermore, we have found that multiple cis-acting elements appear to be required for proper targeting of orb mRNA.

scholarly journals A negative regulatory element in the bcl-2 5'-untranslated region inhibits expression from an upstream promoter

1993 ◽  
Vol 13 (6) ◽  
pp. 3686-3697
Author(s):  
R L Young ◽  
S J Korsmeyer
Keyword(s):  
B Cell ◽  
Cell Lines ◽  
Untranslated Region ◽  
Regulatory Element ◽  
Cell Development ◽  
Negative Control ◽  
B Cell Development ◽  
Negative Regulatory Element ◽  
Cis Acting ◽  
B Lineage

bcl-2 mRNA is present at high levels in pre-B-cell lines but is down-regulated in most mature B-cell lines. To investigate the mechanisms responsible for its developmental control, we studied the regulation of bcl-2 expression in human B-lineage cell lines. Using nuclear run-on assays, we found that bcl-2 transcription decreases in parallel with levels of steady-state mRNA during B-cell development. To define cis-acting elements that regulate bcl-2 transcription, we analyzed the expression of transiently transfected promoter-reporter constructs. We identified a novel negative regulatory element (NRE) in the bcl-2 5'-untranslated region that decreased expression from the bcl-2 P1 promoter or heterologous promoters in a position-dependent fashion. The NRE functions in either orientation but contains distinct orientation-dependent subfragments. Additional analyses demonstrated that multiple, functionally redundant sequence elements mediate NRE activity. Though the bcl-2 NRE is active in pre-B- and mature B-cell lines, chromatin structure of the endogenous NRE differs in these cells, suggesting that its activity or effect may vary during B-cell development. Our results indicate that negative control of transcription initiated at the P1 promoter is an important determinant of the differential expression of bcl-2.

scholarly journals Multiple cis-acting targeting sequences are required for orb mRNA localization during Drosophila oogenesis.

1994 ◽  
Vol 14 (4) ◽  
pp. 2235-2242 ◽  
Author(s):  
V Lantz ◽  
P Schedl
Keyword(s):  
Untranslated Region ◽  
Germ Line ◽  
Critical Role ◽  
Positional Information ◽  
Mrna Localization ◽  
Early Embryo ◽  
Developmental Systems ◽  
Localization Pattern ◽  
Cis Acting ◽  
Anterior Posterior

The targeting of positional information to specific regions of the oocyte or early embryo is one of the key processes in establishing anterior-posterior and dorsal-ventral polarity. In many developmental systems, this is accomplished by localization of mRNAs. The germ line-specific Drosophila orb gene plays a critical role in defining both axes of the developing oocyte, and its mRNA is localized in a complex pattern during oogenesis. We have identified a 280-bp sequence from the orb 3' untranslated region capable of reproducing this complex localization pattern. Furthermore, we have found that multiple cis-acting elements appear to be required for proper targeting of orb mRNA.

scholarly journals An eleven nucleotide section of the 3′-untranslated region is required for perinuclear localization of rat metallothionein-1 mRNA

2005 ◽  
Vol 387 (2) ◽  
pp. 419-428 ◽  
Author(s):  
David NURY ◽  
Hervé CHABANON ◽  
Marilyne LEVADOUX-MARTIN ◽  
John HESKETH
Keyword(s):  
Metal Binding ◽  
Untranslated Region ◽  
Chinese Hamster Ovary Cells ◽  
Chinese Hamster ◽  
Mrna Localization ◽  
Coding Region ◽  
Ovary Cells ◽  
Structural Context ◽  
Deletion Mutagenesis ◽  
Localization Signal

Localization of mRNAs provides a novel mechanism for synthesis of proteins close to their site of function. MT1 (metallothionein-1) is a small, metal-binding protein that is largely cytoplasmic but which can be found in the nucleus. The localization of rat MT1 requires the perinuclear localization of its mRNA by a mechanism dependent on the 3′-UTR (3′-untranslated region). The present study investigates the nature of this mRNA localization signal using Chinese-hamster ovary cells transfected with gene constructs in which either MT1 or the globin coding region is linked to different sequences from the MT1 3′-UTR. Deletion, mutagenesis and antisense oligonucleotide approaches indicate that nt 45–76 of the 3′-UTR, in particular nt 66–76, are required for the localization of either MT1 mRNA or chimaeric transcripts in which a β-globin coding region is linked to sequences from the MT1 3′-UTR. This section of the 3′-UTR contains a CACC repeat. Two mutations that are predicted to alter the secondary structure of this region also impair localization. Our hypothesis is that the perinuclear localization signal in MT1 mRNA is formed by a combination of the CACC repeat and its structural context.

Multiple RNA regulatory elements mediate distinct steps in localization of oskar mRNA

Development ◽  
1993 ◽  
Vol 119 (1) ◽  
pp. 169-178 ◽  
Author(s):  
J. Kim-Ha ◽  
P.J. Webster ◽  
J.L. Smith ◽  
P.M. Macdonald
Keyword(s):  
Pattern Formation ◽  
Untranslated Region ◽  
Anterior Margin ◽  
Regulatory Elements ◽  
Mrna Localization ◽  
Posterior Pole ◽  
Nurse Cells ◽  
Cis Acting ◽  
Cytoplasmic Proteins ◽  
Body Patterning

Pattern formation in the early development of many organisms relies on localized cytoplasmic proteins, which can be prelocalized as mRNAs. The Drosophila oskar gene, required both for posterior body patterning and germ cell determination, encodes one such mRNA. Localization of oskar mRNA is an elaborate process involving movement of the transcript first into the oocyte from adjacent interconnected nurse cells and then across the length of the oocyte to its posterior pole. We have mapped RNA regulatory elements that direct this localization. Using a hybrid lacZ/oskar mRNA, we identify several elements within the oskar 3′ untranslated region that affect different steps in the process: the early movement into the oocyte, accumulation at the anterior margin of the oocyte and finally localization to the posterior pole. This use of multiple cis-acting elements suggests that localization may be orchestrated in a combinatorial fashion, thereby allowing localized mRNAs with ultimately different destinations to employ common mechanisms for shared intermediate steps.

Sign in / Sign up

Export Citation Format

Share Document